1. Field of the Invention
The present invention relates to an image communication apparatus such as FAX. Moreover, the present invention relates to an image communication control method adaptable to a FAX.
2. Description of the Related Art
In recent years, a printer has come into wide use, and various printers have come onto the market. Moreover, low price and high-speed operation of the printer are achieved. As a result, a printer (MFP: multi-function printer) having various functions has come into wide use in addition to a printer having a print function only.
Typically, an inkjet print is given as a low-price printer. In general, the inkjet printer makes much of color reproduction using color ink. Of the foregoing MFP, a high-grade machine utilizes an electro-photographic print system in general.
There is known a FAX machine (hereinafter, referred to as FAX) as an image transmitter/receiver using the foregoing printer function. The FAX is disclosed in JPN. PAT. APPLN. KOKAI Publication No. 2003-274104, for example. By way of the FAX, G3 FAX using an analog line network and G4 FAX using a digital line network such as ISDN are given. Recently, the Internet has come into wide use; as a result, an IP network is applied to the FAX. The FAX (FAX system) using the IP network is called as an Internet FAX (i-FAX). The method of transmitting and receiving image data using an electronic mail is standardized based on IETF (Internet Engineering Task Force) and ITU-T (International Telecommunication Union-Telecommunication standardization sector).
The format of image data transmitted via the i-FAX is limited to a TIFF (Tag Image File Format) file of profile S (simple-rate mode: RFC 2305). Specifically, the image data format is based on the regulations given below.
Image data: binary image encoded via MH method
Resolution: 100 dpi or 200 dpi
Image width: 1728 pixels (equivalent to A4 size)
On the other hand, the G3 FAX smoothly makes communications in a manner that a transmitter receives a message having process-able image data format from a receiver to transmit the image data in a proper format.
The receiver process-able image data format depends on the specifications of an image forming apparatus appended to the receiver. Likewise, this matter is given in the foregoing i-FAX. Thus, a full-rate mode (transmission) is added to the communication procedure of the i-FAX (TTC standard JT-T37: storage and conversion Internet FAX data transmission procedure).
According to the full-rate mode, it is possible to confirm communication status and transmission result using MDN (Message Disposition Notification, RFC 2298) and DSN (Delivery Status Notification, RFC 1894). Specifically, the transmitter side FAX is able to confirm the following information:
(i) whether image data arrives at the transmitter mail server;
(ii) whether image data arrives at the receiver mail server; and
(iii) whether the receiver-side FAX opens and prints an electronic mail attached with the image data.
Moreover, the receiver-side FAX informs the transmitter-side FAX of the capacity (process-able image data format) using reply message disposition notification. By doing so, the transmitter-side FAX can transmit image data having proper data format. In addition, according to the full-rate mode, several image data having different data format is attached to one electronic mail.
Recently, an MFP supporting an i-FAX function in addition to the foregoing ordinary (public) FAX function has been proposed. The MFP can designate several destinations (addresses) to transmit an image to these destinations all together, using the i-FAX function. Moreover, the MFP can simultaneously designate ordinary FAX destination and i-FAX destination to transmit an image to these destinations all together, using both ordinary FAX function and i-FAX function. The function of transmitting the image to these destinations all together calls a broadcast (multi-destination) transmission function.
The G3 FAX makes communications in a manner that a transmitter reads image data and transmits it after receiving notification having process-able data format from a receiver. By doing so, image transmission is possible without reducing image quality.
In a simple mode (200 dpi)-enabled i-FAX, the transmitter side has no means for specifying the resolution of the receiver side. For this reason, the transmitter side transmits a limited image, that is, TIFF image of profile S.
However, according to the broadcast transmission using both ordinary FAX function and i-FAX function, there is the case of transmitting image data having a resolution exceeding the maximum resolution supportable by the receiver. This results from the following reason. Specifically, the receivable maximum resolution is different among broadcast transmission destinations (several transmission destinations supporting ordinary FAX function and i-FAX function).
For example, user designates the maximum resolution, that is, Super fine mode (15.4 mm×16≈400 dpi), ordinary FAX destination and i-FAX destination. In this case, image is scanned using the maximum resolution. Thus, image data having the designated maximum resolution is intactly transmitted to the ordinary FAX destination. However, the image data having the designated maximum resolution is not transmitted to the i-FAX destination, which does not support the maximum resolution. For this reason, the image data having the maximum resolution image is converted into image data having low resolution via image processing using software (simple thinning). By doing so, the image data having low resolution is not transmitted to the i-FAX destination.
However, image quality degradation occurs due to the foregoing simple resolution conversion. This is a phenomenon, which happens resulting from the following reason. Because, resolution conversion such as thinning is made with respect to binary image data after binarized by error diffusion processing. For this reason, image density reproduction is lost.